Equivalent Elastic-Plastic Model of BCC Lattice Structures

The lattice structures are widely utilized in support structures and internal fillings, playing a significant role in improving manufacturing efficiency and optimizing structural performance. However, due to the complex microstructure of lattice materials, it is challenging to describe them using refined finite element models. The development of an equivalent performance model for these materials, employing a periodic single cell to represent the internal structure for the comprehensive lattice system, can significantly improve computational efficiency and provide an effective method for supporting system optimization. Given the substantially reduced stiffness of lattice structures in comparison to solid materials of analogous dimensions, the equivalent elastic limit of their surrogate models is markedly lower than the inherent elastic limit of the materials themselves. Hence, when deploying a single-cell equivalent performance surrogate model, it is imperative to calibrate the equivalent stress-strain curve based on the lattice configuration. This study establish a single-cell equivalent performance surrogate model for the Body-Centered Cubic (BCC) lattice structure. Through finite element analysis, it derives the equivalent stress-strain curves under various parametric conditions, elucidating the influence trends of different design parameters on the elastic-plastic transformations of the BCC lattice. The computational results suggest that the equivalent tensile modulus is proportional to the fourth power of the radius-to-length ratio, whereas the equivalent tangent modulus is proportional to the sixth power of this ratio.